The best time is 14: 00 ~ 19: 00. Human activities are controlled by the biological clock. Arranging exercise time according to the law of "biological clock" is more conducive to health. Fitness in winter is best between 14:00- 19:00 in the afternoon. At this time, the outdoor temperature is relatively high, and the temperature of the human body is relatively high, and the physical strength is relatively abundant. It is easy to get excited, and it is easier to enter the state of exercise. Afternoon: (14: 00 ~ 16: 00): It is a good opportunity to strengthen physical strength, and the muscle endurance is 50% higher than other times. Dusk: (17: 00 ~ 19: 00): Especially when the sun goes down, the human body's exercise ability reaches its peak, and the vision and hearing are more sensitive, and the heart rate and blood pressure also rise. Not suitable for after-meal exercise: at this time, more blood flows to the gastrointestinal department to help food digest and absorb. At this time, exercise will hinder the digestion of food, and over time, it will lead to diseases of the gastrointestinal system and affect health. Therefore, it is best to sit still or lie down for 30 ~ 45 minutes after meals and exercise. After drinking: alcohol is absorbed into the blood and enters the brain, heart, liver and other organs. At this time, exercise will increase the burden on these organs. Compared with after-dinner exercise, drinking exercise has a greater negative impact on the human body. Health reminder: Outdoor fitness is not as early as possible. In the cold winter, many people choose morning exercises to enhance their immunity. However, isn't outdoor fitness the sooner the better? Relevant health experts suggest that outdoor fitness in winter should be carried out after sunrise. It is understood that the ground temperature is low before sunrise in winter, and the content of pollutants such as carbon monoxide and carbon dioxide released in the air in the morning is high. In addition, harmful pollutants such as nitrogen oxides, hydrocarbons and lead in automobile exhaust also gather on the ground. If people get up early to exercise, they will inhale a lot of smoke and toxic gases. Long-term exercise in this environment may lead to fatigue, dizziness, pharyngitis and other diseases, which are harmful to the body. Fitness in winter should be around 10 hour. At this time, the sun shines on the ground after coming out, which makes the atmosphere begin to convection up and down, and the polluted air spreads to the sky, which will reduce the harm to the human body. In addition, the temperature is low in winter morning, and it will not slowly ease until half an hour after the sun comes out. Strengthening exercise and promoting metabolism can not only make you thinner, but also increase your appetite. You should keep running!